I am now really confused. I am on XB1. I have followed @BleedingUranium 's FANTASTIC guide on FOV and USA. Because enemies are literally hard enough to see directly in front of my face, I play on the minimum FOV (50) for the most non-ADS zoom possible. I have tried ADS FOV settings ON and OFF, and I still can't get my 1x zooms to render correctly. Effectively, I can never use a Nydar or a Reflex because it makes it impossible to see anything by zooming my sight picture out every time. It's so jarring. I have just been using iron sights exclusively recently and as a result have been performing much much better.

How do I properly set up my FOV and ADS so I can use 1x sights? Is this a bug?

The default behavior (ADS FoV scaling off) makes it so a 1x zoom sight is 1x zoom of 55 FoV. So if you have a set FoV of 80 then a 1x sight will still be 55.

ADS FoV Scaling On makes it so zoom is calculated based on your set hipfire FoV rather than the default of 55. So now with a set FoV of 80 the 1x sight will now be 80. I guess it somehow breaks since your set FoV is lower than the default of 55 and it reverts to the default fov scaling or something like that.

I tested and found exactly this effect this morning, but obviously I was dumb enough to not take screenshots. I don't know when I might be able to play again reproduce it. However, I would expect anyone on XB1 can set their FoV to the minimum, slap on a 1x, and mimic the same effect.